Voltage sequencing circuit for powering-up sensitive electrical components

• US 6,333,650 B1
• Filed: 12/05/2000
• Issued: 12/25/2001
• Est. Priority Date: 12/05/2000
• Status: Expired due to Term

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Armstrong, Michael, Heitkamp, Ross, Amin, Dilip A., Wu, Chang Hong
• Primary Examiner(s): Zweizig, Jeffrey
• Application Number:
  US09/729,239
• Time in Patent Office: 385 Days
• Field of Search: 327/142, 327/143, 327/198, 327/530, 327/534, 327/535, 327/537, 327/540, 327/545
• US Class Current: 327/143
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C

Abstract

A voltage sequencing circuit powers-up electrical systems by sequentially enabling a series of power supply lines to the electrical system. After each power supply line is enabled, the voltage sequencing circuit waits a pre-programmed delay time before enabling the next power supply line. The delay time allows the newly enabled power supply line to settle. Additionally, the voltage sequencing circuit constantly monitors previously enabled power supply lines while continuing to enable the remaining power supply lines. If any of the previously enabled lines fail, the voltage sequencing circuit disables the power supply line before reinitiating a complete power-up sequence.

Claims

1. A voltage sequencing circuit comprising:

a plurality of electrical power sources configured to supply respective electrical components having differing power requirements;

a power monitor connected to outputs of the plurality of electrical power sources, the power monitor detecting failures in the electrical power sources; and

decision logic connected to the plurality of electrical power sources and to an output of the power monitor, the decision logic performing a power-up sequence by sequentially enabling the plurality of electrical power sources and verifying, based on outputs from the power monitor, that an enabled one of the electrical power sources is stable before enabling a next one of the plurality of electrical power sources.

2. The voltage sequencing circuit of claim 1, wherein the decision logic disables all of the plurality of electrical power sources when a failure is detected by the power monitor in any of the enabled electrical power sources.

3. The voltage sequencing circuit of claim 2, wherein the decision logic waits a predetermined time period after enabling a power source before verifying that the enabled power source is stable.

4. The voltage sequencing circuit of claim 2, wherein the decision logic reinitiates sequential enablement of the power sources after disabling all of the plurality of power sources.

5. The voltage sequencing circuit of claim 1, further comprising

at least one light emitting diode connected to the decision logic, the at least one light emitting diode providing a visual indication of the result of the power-up sequence.

6. The voltage sequencing circuit of claim 1, wherein the power monitor includes a plurality of power monitor circuits, each power monitor circuit being connected to the output of a respective one of the plurality of electrical power sources.

7. The voltage sequencing circuit of claim 1, wherein the sequential order of the plurality of electrical power sources is arranged in increasing order of power source voltage.

8. The voltage sequencing circuit of claim 1, wherein the sequential order of the plurality of electrical power sources is arranged in decreasing order of power source voltage.

9. The voltage sequencing circuit of claim 1, wherein the power monitor detects a failure in one of the electrical power sources when the power monitor detects one of a loss of power and a power spike outside of a predefined threshold.

10. The voltage sequencing circuit of claim 1, wherein at least one of the power sources supply power by initially ramping the supplied power.

11. A device comprising:

an electrical system that includes a plurality of circuits designed to be powered from different electrical power sources; and

a voltage sequencer coupled to the electrical system and supplying power to the plurality of circuits in the electrical system, the voltage sequencer including;

a plurality of power regulators for supplying the power to the plurality of circuits in the electrical system,

a power monitor connected to outputs of the plurality of power regulators, the power monitor detecting failures in the power supplied by the power regulators, and

decision logic connected to the plurality of power regulators and to outputs of the power monitor, the decision logic performing a power-up sequence of the electrical system by sequentially enabling the plurality of power regulators and verifying, based on the outputs from the power monitor, that an enabled one of the power regulators is producing stable output power before enabling a next one of the plurality of power regulators.

12. The device of claim 11, wherein the electrical system is a network switch.

13. The device of claim 11, wherein the decision logic disables all of the plurality of power regulators when a failure is detected by the power monitor in the power supplied by any of the enabled plurality of power regulators.

14. The device of claim 13, wherein the decision logic waits a predetermined time period after enabling a power regulator before verifying that the power supplied by the enabled power regulator is stable.

15. The device of claim 13, wherein the decision logic reinitiates sequential enablement of the power regulators after disabling all of the plurality of power regulators.

16. The device of claim 11, further comprising

a light emitting diode connected to the decision logic, the light emitting diode providing a visual indication of a result of the power-up sequence.

17. The device of claim 11, further comprising:

a control component coupled to the decision logic, the control component receiving signals from the decision logic that indicate the result of a power-up sequence.

18. The device of claim 11, further comprising:

a control component coupled to the voltage sequencer, the control component transmitting signals to the voltage sequencer that control the operation of the voltage sequencer.

19. The device of claim 11, wherein the power monitor includes a plurality of power monitor circuits, each power monitor circuit being connected to the output of a respective one of the plurality of power regulators.

20. The device circuit of claim 11, wherein the sequential order of the enablement of the plurality of power regulators is arranged in increasing order of supplied power level.

21. The device of claim 11, wherein the sequential order of enablement of the plurality of power regulators is arranged in decreasing order of supplied power level.

22. The device of claim 11, wherein the power monitor detects a failure in power supplied by one of the power regulators when the power monitor detects one of a loss of power and a power spike outside of a predefined threshold.

23. The device of claim 11, wherein at least one of the plurality of power regulators supply power by initially ramping the supplied power.

24. A method for powering-up an electrical system to receive power from a plurality of different power sources, comprising:

(a) enabling a first one of the plurality of power sources to source power to the electrical system;

(b) waiting a predetermined period for the power from the first power source to settle;

(c) beginning to monitor an output of the first power source for a failure in the sourced power;

repeating (a), (b) and (c) for each additional power source in the plurality of power sources; and

disabling all of the enabled ones of the plurality of power sources when any of the monitored power sources fail.

25. The method of claim 24, wherein the predetermined period is individually set for each of the plurality of power sources.

26. The method of claim 24, further including:

displaying a visual indication of a result of enabling each of the plurality of power sources.

27. The method of claim 24, wherein the plurality of power sources are enabled in a sequential order from lowest voltage source to highest voltage source.

28. The method of claim 24, wherein the plurality of power sources are enabled in a sequential order from highest voltage source to lowest voltage source.

29. The method of claim 24, wherein monitoring the outcome of the plurality of power sources for a failure in the sourced power includes detecting a loss of power or a power spike.